Abstract
The analysis conducted on the sea water and sea-bottom sediments at Otozu-Hakuchi in Beppu Bay showed polluted inflow spread into the surface portion of the sea water, with minor mixing in the vertical direction owing to the density difference between polluted inflow and authentic sea water. This stratifying phenomenon appeared more clearly in summer. The COD and sulfide content in the sediment were almost identical to those in more polluted estuary, irrespective of the degree of pollution of the sea water above the sediment, which indicated pollutants accumulate into the bottom sediment. A good correlation between the number of sulfate-reducing bacteria in the sediment to sulfide content in the sediment was observed in summer season.
